Wednesday, September 10, 2014

Cold Front Passing Through

Those narrow strips of reflectivity on the NEXRAD radar are actually the leading edge of a strong cold front, which will continue to push south and east today. Much cooler weather is on the way for tomorrow and even more so on Friday, where some places will be stuck in the 40s! 

Sunday, September 7, 2014

Severe Weather ---> Excessive Cold ----> Snow Flurries?

After a tranquil Sunday and relatively quiet Monday, the world of weather in the Midwest will become much more active by Tuesday.  A developing area of low pressure will push through the Midwest early Tuesday and drift NE through Wednesday.  East of the system a more humid and unstable airmass will encompass the shaded area.  Severe T-storms should develop in and around the shaded areas. Damaging winds and large hail appear to be the primary threats.

Flooding will also pose troublesome with much of the Midwest saturated from recent heavy rains.

As the system pulls away Thursday, winds will shift out of the northwest and usher in the coldest air of the season. It will certainly feel like fall with a cool dry airmass in place. High temperatures on Friday will be running 15-20 degrees below normal across most of the central part of the country. Areas north of a line from Green Bay to Minneapolis to Rapid City could deal with some frost by the end of the week, or maybe even a hard freeze. Much of the Midwest will see highs in the 50s and 60s respectively.

On the left is the latest 6-10 day temperature outlook from the Climate Prediction Center.  It shows the likelihood of temperatures below the normal mean temperature during a specified time period.  For those that follow these maps, dark shades of blue are extremely rare. In recent days the dark blues are appearing as frequently as the did earlier in the Spring during the winter that never seemed to end. Another prolonged period of even colder weather has popped up in the computer models. The European model has another strong cold front passing through early next week with accumulating snow in northern Minnesota, we will see how this one plays out in coming days.

The WPC is forecasting high temperatures in the 50s for the NW half of the Midwest. Going conservative 5 days out, these highs could even be lower than depicted on the right. High pressure builds in for Thursday night and Friday night, which could set the stage for near record low temperatures during this time period.

With it being the first major shot of cold air, we will closely watch how the models handle it to get a gauge on the rest of the summer and into Autumn for future forecasts.

Just for kicks, below is the EURO model for next Monday as the cold front pushes through...

Friday, September 5, 2014

Exceptional Chill on the Way Late Next Week

The coldest air of the season is building up in northern Canada and will dive south into the continental United States by late next week.  The jet stream will pinch out a trough in the midsection of the country and allow for the ushering of much cooler air.  Temperatures will run 10-20 degrees cooler than average. The map on the left shows the likelihood of below normal temperatures, notice the substantial area of dark blues encompassing the northern Great Plains. This weather will likely bring the first 30s in northern Minnesota and a couple snow flakes cannot be ruled out, as 850mb temperatures dip below 0C. The map on the bottom shows the expanse of the cold, with the 0C line dipping excessively south.


Just to give a snapshot of what some of the models are is the latest EURO model run for minimum temperatures next Friday night and Saturday morning. Showing widespread lows in the 20s! While this scenario is extremely unlikely, record low temperatures may be within reach. The GFS is outputting similar, yet more conservative numbers. One rule of thumb this summer is that the EURO does tend to go cold a week out, it will be interesting to watch the cold unfold in the models throughout the next several days.


After record high temperatures across the Midwest the past few days, this weekend will begin to serve as relief for most areas.  By Sunday we return to near average highs and stay around average until late next week when the reinforcing shot of cold air comes in! Happy Fall.